If you take a grape, slice it almost in half, so just a small bit of skin remains connecting the two halves.

1) Place the grape in the microwave and set on high for 1min (doesn't take this long)
2) the two halves pickup and focus radiation into the skin "bridge" part.
3) The skin follows the process that happens when things are heated up
eg. Solid (ice) > Liquid (Water) > Gas (steam/vapour) > Ionised gas (plasma)

4) These steps occur in about 0.2sec. Quite entertaining if you're bored.

Well early 80's we had a jock pay sgt. Nice bloke but liked a drink.
Not the most switched on sort after a skinful and he could sup a skinful or two.
Came into the mess early hours felt peckish, could only find some eggs ready for breakfast so he popped a couple in the microwave
Explode, well the Mess staff exploded the following morning when they had to clean up the mess.
john